1. Field of the Invention
The present invention relates to the art of bookbinding and, particularly, to the completion of manufacture of a book by forming the folds which define articulation areas in the cover and subsequently applying the thus shaped cover to a previously produced inner book. More specifically, this invention is directed to apparatus for use in performing a "casing-in" procedure in a book production line and, especially, to apparatus which permanently produces all of the requisite contours in a book cover immediately prior to affixation of the cover to a completed inner book. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
In the industrial production of "hard cover" books, i.e., in bookbinding procedures performed on a commercial scale, the final manufacturing steps which are performed are incident to the application of the book cover to the finish-machined inner book. The mating of the cover to the inner book is known in the art as "casing-in". The "casing-in" procedure, in the prior art, has been followed by an operation known as "burning-in of the folds" in which the areas about which the boards of the book cover articulate, i.e., the hinges or "folds", are formed. The "burning-in" procedure may be coupled with a step of "pressing of the book as a whole".
An example of a prior art casing-in machine is shown in published German Patent Specification 14 36 086. Inner books, standing on the front "cut" thereof, are fed into this prior art casing-in machine where they are engaged by saddle plates which comprise parts of a vertical conveyor. The thus engaged inner books are transported upwardly past oppositely disposed adhesive-applying rollers. These rollers deposit an adhesive over substantially the entire outer surfaces of the flyleaves of the inner book. A book cover, extracted from a magazine, is delivered to a shaping and folding station in which the back portion of the cover is given its requisite rounded shape through the action of a shaping rail and cooperating folding rails. The book cover with its shaped back is then moved into the path of movement of an inner book so that the rounded spine portion of the inner book will engage the complementary shaped rounded back portion of the book cover. The thus mated cover and inner book will pass between pressure rollers which ensure intimate contact between the insides of the covers and the adhesively coated flyleaves. The book is then released from the supporting saddle plate and delivered to a "burning-in" station.
An example of prior art "burning-in" apparatus may be seen from U.S. Pat. No. 2,921,322, the "burning-in" apparatus being shown as combined with a "casing-in" apparatus to form a final assembly-line stage of a bookbinding operation. The "burning-in" apparatus of U.S. Pat. No. 2,921,322 is defined by a multiplicity of pressing devices which are disposed in a straight row with uniform mutual intervals therebetween. Each of the pressing devices includes a pair of pressing plates which are located opposite to one another with a variable interval. These pressing plates apply compressive force to the sides of an engaged book. Heated rails for "burning-in" the folds, i.e., forming the hinge joints of the book, are associated with the pressing devices. These heated rails operate in pairs to shape the book cover folds. The rails are located on a carriage and, simultaneously with forming the folds, serve as transport mechanisms to move the books stepwise from pressing station to pressing station.
The "burning-in" of the folds of the book cover, as accomplished in the prior art with the above-briefly described apparatus, is intended to produce a recessed, triangular region in the covering material of the cover along the inner edges of each of the two oppositely disposed cover boards. This recessed "fold" is, as noted, produced through the application of heat and pressure. In order to ensure that the fold will retain its shape once formed, adhesive bonding of the covering material to the underlying fold region of the inner book is affected via the application of a glue dispersion in the fold region of the inner book.
The reliable and repetitive production of a properly functioning and aesthetically acceptable product requires that the heated rails employed to "burn-in" the book cover folds cause plastic flow of the covering material of the book cover. Restated, permanent deformation of the covering material is necessary in order to counteract the restoring action of the material. The formation of the cover folds must be accomplished in such a manner that the glue dispersion in the region between the book cover covering material and inner book will be heated sufficiently to insure the formation of a bond whereby transport of the book immediately upon its release from the "burning-in" apparatus will be possible.
Prior art casing-in/burning-in systems have experienced problems due to misalignment between the cover and inner book. Also, indistinct cover fold edges have occurred as a result of inaccurate engagement with the rails for "burning-in" the folds. The problem of indistinct edges has not been overcome by resort to complicated and expensive alignment apparatus.
In the prior art, as briefly described above, the inner book is cased in the book cover at a time when the portions of the covering material which are to be shaped to produce the cover folds are in a stretched-out condition, i.e., the cover is adhesively bonded to the flyleaves of the inner book and closed. This has resulted in the "burning-in" process being difficult to perform. This difficulty, in part, results from the fact that, with the covering material already in a stretched condition, it is difficult to obtain, by further heat assisted stretching, the additional lengths of material required to form the folds. It is thus possible for the covering material to tear, or for compression creases to occur at the flyleaves, during the "burning-in" of the folds. Further, residual tensile stresses in the covering material in the fold regions, these stresses acting in a direction which tends to produce separation between the peaks of the folds and the underlying flyleaves, can lead to disruption of the adhesive bond when the pressure applied by the heated rails is relieved.
A further problem in the prior art is the overheating of the surface of the covering material which may result in the marring thereof and/or at least partial disruption of the adhesive bond between the covering material and underlying cover boards.